The error codes are... a suggestion at best. Just as the Windows errors in general are I believe.

I got

Error code: POL-0001
An unexpected problem occurred.
Persistent problems can be reported
from Service & Support.

today or so, when trying to log in on a character that was not paid for, but got freebied for, while I had not been back to the PlayOnline Viewer yet.

If you can log in on one account on a clean install, and not on another, there is something wrong with another.

Not sure how you could escalate it more though. :\

If they can offer a free subscription, only then I would try that option (again).

Still, I'd suggest you keep trying. I have personally had only good experiences with the support (only e-mail, never chat), but I never had too big troubles (one example being un-linking the physical security token which had its battery die after only 13 years... dang).